/*���ǿ�����MyController�и�expr������ʽ����һ��$watch��������*/
var app = angular.module('App', []);

app.controller('MyController',
    function ($scope, $parse) {
        $scope.$watch('expr', function (newVal, oldVal, scope) {
            if (newVal !== oldVal) {
                var parseFun = $parse(newVal);
                $scope.parsedValue = parseFun(scope);
            }
        });
    });